40 CFR § 141.535 - What if my system uses chloramines, ozone, or chlorine dioxide for primary disinfection?

---
identifier: "/us/cfr/t40/s141.535"
source: "ecfr"
legal_status: "authoritative_unofficial"
title: "40 CFR § 141.535 - What if my system uses chloramines, ozone, or chlorine dioxide for primary disinfection?"
title_number: 40
title_name: "Protection of Environment"
section_number: "141.535"
section_name: "What if my system uses chloramines, ozone, or chlorine dioxide for primary disinfection?"
chapter_name: "ENVIRONMENTAL PROTECTION AGENCY"
subchapter_number: "D"
subchapter_name: "WATER PROGRAMS"
part_number: "141"
part_name: "NATIONAL PRIMARY DRINKING WATER REGULATIONS"
positive_law: false
currency: "2026-04-05"
last_updated: "2026-04-05"
format_version: "1.1.0"
generator: "[email protected]"
authority: "42 U.S.C. 300f, 300g-1, 300g-2, 300g-3, 300g-4, 300g-5, 300g-6, 300j-4, 300j-9, and 300j-11."
regulatory_source: "40 FR 59570, Dec. 24, 1975, unless otherwise noted."
cfr_part: "141"
---


# 141.535 What if my system uses chloramines, ozone, or chlorine dioxide for primary disinfection?

If your system uses chloramines, ozone, or chlorine dioxide for primary disinfection, you must also calculate the logs of inactivation for viruses and develop an additional disinfection profile for viruses using methods approved by the State.